Apparatus for manufacturing tubing



Jan. 27, 1959 c. E. HlCKMA-N ET AL 7 APPARATUS FOR MANUFACTURING TUBINGFiled Sept. 5, 1951 I I v 5 Sheets-Sheet 1 I1E=E INVENTOR. 1

CHARLES E. HICKMAN y ALLEN L. GOLDSMITH Jan. 27, 1959 c. E. HICKMAN ETAL 2,870,522

' APPARATUS FOR MANUFACTURING TUBING Filed Sept. 6, 1951' 3 Sheets-Sheet2 Ila-=4.-

/ 'i z I 76: 74, ll

i III-31.7

F15 INVENTOR.

CHARLES E. HICKMAN By ALLEN LGQLDSMITH Jan. 27, 1959- E. HICKMAN ET ALAPPARATUS FOR MANUFACTURING TUBING Filed Sept. 6, 1951 3 SheetsSheet 3CHARLES E. HICKMAN BY ALLEN LGOLDSMITH United States Charles E.'Hickmanand Allen L. Goldsmith, Adrian, Mich.

Application September 6, 1951, Serial No. 245,404

'5' Claims. (CI. 29-33) v This invention relates to apparatus forcontinuously forming and coiling small diameter thin wall metal tubing,and hasparticular .reference to a process and apparatus operable toproduce a continuous, free ended coil of extruded metal tubing, such asaluminum tubing, which closely approximates the dimensional tolerancesand wall thicknesses of cold drawn tubes but without requiring a drawingoperation.

Normally the length of material issuing from an ex trusion press islimited to the length of the run out table extending from the mouth ofthe press. The run out table in turn is limited by the physical size ofthe building and the practical limits on the length of the materialwhich may be conveniently handled without damage. In most shops thiswould be from seventy to one hundred feet.

Because of the variations in the speed of issuance from an extrusionpress of a material such as small size, relatively thin wall tubing,even with uniform pressure upon the billet of metal from which thematerial is made, it is customary in the trade to employ persons knownas pullers who grasp the emerging end of the tube as it comes from thepress with suitable clamps and proceed along the side of the run outtable applying enough tension to keep the tube from kinking but notenough to cause it to separate.

There are several variables which have an influence upon the uniformityof the speed with which such material may be extruded: namely, thetemperature to which the billet is heated, the temperature to which theconv.tainer which holds the metal as it is being pushed into the die isheated, the varying length of the billet as it is being extruded, andthe pressure which is exerted upon the billet as it is being extruded,to name but a few.

'Becausethe resulting tube represents such a small part of the-initialbillet, very slight changes in temperature and forces acting upon thebillet will cause such variations in the speed of the tube as it issuesthrough the die that it is impractical to use constant speed-mechani--.ca lmeans to supplantthe puller.

, This invention contemplates a methodof and apparatubing and beingdriven so as to exert a constant pull onthe tubing so as to followthe-instantaneous change Lin speedof the tubing as itemerges from thepress.

=A. principal object of the invention, therefore, is to provide anovelmethodof and-apparatus for continuously formingand-coiling smalldiameterthin wall metal tub- .rifl .such as. aluminum'tubing, Withoutthe necessity of a drawing operation.

1 v gAnotherv object of the invention is to-providea method of andapparatus for coiling small diameter thin Wall :tubingin helical coilswith a free end.

. Another; object of the inventionis toprovide a method Patented Jan.27, 9

2 of and apparatus for rapidly cooling extruded metal tubing so thatsuch tubing may be handled without damage to the tubing and without thetubing sticking to itself or burning materials in contact with it.

Other and further objects of the invention will be ap parent from thefollowing description and claims and may be understood by reference tothe accompanying drawings, of which there are three sheets, which by wayof illustration show a preferred embodiment of the invention and what wenow consider to be the best mode in which we have contemplated applyingthe principles of our invention. Other embodiments of the invention maybe used without departing from the scope of the present invention as setforth in the appended claims.

In the drawings:

Fig. 1 is a fragmentary sectional view of an extrusion press embodyingour invention;

Fig. 2 is an enlarged fragmentary sectional view of the die parts in thecoalescence chamber;

Fig. 3 is a fragmentary sectional view of the cooling device;

Fig. 4 is a plan view of the cooling device shown in Fig. 3;

Fig. 5 is a side elevational view of the coiling device;

Fig. 6' is a plan view of the coiling device. shown in Fig. 5; and

Fig. 7 is a schematic illustration of the control system for the directcurrent motor which drives the coiling device.

The apparatus embodying our invention comprises in general an extrusionpress 10 (Fig. l), a tube cooling device 12 (Fig. 3), a coiling device14 (Fig; 5), the, latter being provided with means including a directcurrent motor 16 for driving the rollers of the coiling device so as toexert a constant pull on the tubing as it emerges from the extrusionpress.

As shown in Figs. 1 and 2, the press comprises in general a platen 20having an'opening through which the die holder 22 extends, the dieholder22 being secured in position against the, platen 20 by thereciprocable die locks 24. A die backer 26 and die housing 28 arepositioned in a cavity in the die holder 22. The backer 26 and housing28 are securely fixed as illustrated relative to each other and to thecylinder 30 so that the billet of metal 32 in the cylinder 30 will flowunder the influence of heat and pressure into the coalescence chamber34.

The coalescence chamber 34 comprises an annular chamber formed byhollowed out portions of the backer 26 and the housing 28, the latterbeing provided Witha plurality of cylindrical passages'36 aifordingcommunication between the chamber 34 and the cylinder 30. The passages36 are symmetrically arranged parallel to the axis of the chamber 34.The cylinder 30 is formed in a cylinder block 38 which as arranged inFigs. 1 and 2 abuts the die housing 28.

Pressure is applied-to the billet 32 in the cylinder 30 by means of aseal plug 40 and a ram 42. As is customary, the die parts, the billet,and the containing cylinder are maintained at suitable temperaturesduring operation of the press, and pressure is applied by the ram 42 tothe billet 32 to cause it to flow, the pressure required being dependentto some extent upon the temperature to which the parts are heated andbeing of the order of 100,000 lbs. per square inch.

The backer 26,whichforms one wall of the coalescence chamber 34, isprovided with a circular opening 44 disposed concentrically relative tothe axis of the chamber 34 and through which opening the metal to beextruded flows in the form of a hollow tube 46. An annular die member 48of hard material, such for-example as tungsten carbide, is seatedagainst the face of the backer26 and disposed around the opening 44 andfonns a die for determining the outside diameter of the tubing to beextruded. While the die member 48 is seated in a recess in the backer26, it may have a loose or floating fit therein so that it is free toshift in a plane normal to the axis of the chamber 34.

The hub 56 of the housing 28 is provided with a socket 50 which looselyreceives the base 52 of the core so that the core 54 has a loose orfloating support on the hub 56 of the housing 28. The core is disposedon tne axis of the chamber 34 and projects into the an :ir die 48 inspaced relation therewith so as to form annular opening between the core64 and the die 43.

The metal to be extruded flows from the cylinder through the passages 36into the chamber 34 pletely fills the same. In the chamber 3 th alescesand completely fills the chamber and the core and the metal flows fromthe charn between the core 54 and the die 48 to form the sear iessextruded tubing 46.

While the core 54 has a loose fit in the socket 5-5 it is held in piaceby the pressure which the metal in chamber 3 exerts upon the base 52 ofthe core 54-. The pressure exerted by the metal in the chamber 34 as itflows through the annular opening between the core 54 and the die it;tends to cause the core 5-ito center itself in the annular opening inthe die 48. if the die is also free to float, the pressure exerted bythe metal in the chamber A as it flows through the annular openingbetween the core 54- and the die 48 will also tend to cause the die 4?to center itself with respect to the core 5d. The core 54 may also, ifdesired, be formed of hard material, such as tungsten carbide.

As the billet 32 is used up, the seal plug 41 moves within apredetermined distance of the die housing 2'5. At this time the cylinderblock 3%, which is moved by a hydraulic piston and cylinder unit (notshown), is caused to move away from the surface of the housing 28 andover the outer surface of the part of the billet remaining in thecylinder 30 and also over the seal plug 40 until the remaining metal ofthe billet, usually referred to as the butt, and the seal plug 40 areexposed. The ram 42, which is also actuated by a hydraulic piston andcylinder unit (not shown), is retracted and the shear blade 58 actuatedby the power cylinder 59 is moved downwardly across the exposed rearface of the die housing 28, thereby separating the butt from the housinand permitting the butt and seal plug 40 to fall out of the Way. Thecylinder block 38 is then brought forward into contact with the rearface of the die housing 23, another billet is introduced into thecylinder 30, the seal plug is replaced, and the ram 42 is advanced foranother cycle. As the metal of the billet is again forced into the holes36 of the die housing, because of the pressure to which the metal issubjected it comes into intimate cohesive contact with that left withinthe die housing and all vestige of air is compressed and expelled, andthe metal of the new billet becomes a homogeneous mass with thatremaining of the one which preceded it.

It has been found more convenient to permit the die holder 22 to remainin position through several cycles or until it becomes necessary toremove the die parts. The die holder may be removed by causing the dielocks to separate and then by pushing the die holder 22, the die parts26 and 28, the butt, and the seal plug 40 through and away from thecontainer by the continued forward movement of the ram 42.

In this instance the die holder 22 and the die parts and 2S arecompletely withdrawn through the opening in the platen 29 and the buttmay then be sheared with a shearing mechanism (not shown) like 58 butmounted on the front side of the platen 2i). Following such op erationthe ram 42 is then withdrawn, the container 3% moved back, the dieholder 22 and the die parts carried thereby again introduced through theplaten and locked All in place by the die locks 24. The container 33 isthen brought forward in contact with the rear face of the die housing, anew billet is introduced into the cylinder 30, and the operationscontinued as previously mentioned.

As shown in Figs. 1 and 2, the extrusion press is operable to form thehollow seamless tubing 46 and to discharge the same, the temperature ofthe extruded tubing as it leaves the die being in the neighborhood of700 to ll0O P. if aluminum tubing is being formed. While the process andapparatus are particularly adapted for use in forming aluminum tubing,they may be used in connection with the formation of tubing of othermetals, such for example as magnesium.

Speaking now about aluminum tubing, as it is extruded from the press itis so hot that it has insuflicient strength to withstand winding withoutcollapsing, and it is readily subject to scoring and abrading andsticking to itself. it therefore is highly desirable to rapidly cool thetubing as it is extruded, and for this purpose we have provided thecooling device shown in Figs. 3 and 4. The cooling device comprises atank 60 of cooling liquid, such as water, having tube entering and tubeexit openings 62 and 64 arranged in line with and at the same elevationas the tubing as it is extruded from the press. As the tubing emergesfrom the press it passes through a series of slots 66 formed in a seriesof partitions 68, thence through the entrance opening 62 to the tank 60,thence through the tank 66, thence through the exit opening 64, andthence through another series of slots 70 formed in another series ofpartitions 72. The openings 62 and 64 to the tank 60 are formed by slotsin the end walls '74 of the tank and by removable partitions 76 so thatwater may stand in the tank 6b to a higher level than the openings 62and 64. The removable partitions 76 may be removed when the tubing 4-6is first extended through the cooling device. Therefore, it is notnecessary to thread the tubing 46 through the cooling device, but merelyto lay it in the slots 66 and 7t and the slots in the end walls 74 whichform the openings 62 and 64. Thereafter the partitions '76 may beinserted, leaving a slight clearance around the tubing so that water mayflow from the tank 6! outwardly through the openings 62 and 64.

Water enters the tank 60 through the supply pipe 78 which communicateswith a horizontally extending pipe 80 disposed below the tubing 46.Water is maintained at a predetermined height in the tank above the tube46 by the overflow pipe 32 and by the labyrinth of weirs created by theslots 66 and 70 in the partitions 68 and 72. The partitions 68 and 72form individual compartments, each of which has a restricted drainopening 84, in the bottom thereof. The partitions 68 and 72 arepartially enclosed by troughs 86 to which drain conduits 88 areconnected. The slots 66 and 76 in the partitions 68 and 72 have a fairlyclose fit around the tubing 46 but also provide sufiicient clearance topermit water to flow from the tank 60 through the slots 66 and 70 andaround the tube so as to cool the same as it enters and leaves thecooling device. The partitions 76 limit the flow of water from the tank60 around the tubing 4-6, and the water which does escape through theopenings 62 and 64 spills seriatim intothe several compartments formedby the partitions 68 and 72, the water escaping from the compartmentsthrough drain holes 84. This labyrinth of weirs permits the water toescape from the tank at such a rate that it will not flow beyond theconfines of the outermost partitions 68 and 72.

The horizontally extending pipe 80 functions as a distributor and isprovided with a series of jets 90 for discharging jets of water againstthe tubing 46 as it moves through the tank 60, the jets functioning todislodge the.

steam enveloping the tube and formed by the water as it is heated by thetube 46.

In one installation we have made the cooling device function to reducethe temperature of the aluminum tubing leaving the cooling device toapproximately F. In this installation the tubing moved through theas'rosszz cooling device at speeds between 100and 300 feet per minute,depending upon the size ofthe tubing. With the size of the tubing beingformed this would require cooling approximately twelve pounds ofaluminum per minute 700 F.

From the cooling device the tubing 46 moves to the closely positionedcoiling device shown in Figs. Sand 6. The coiling device includes twoperipherally grooved drive rollers 92 and 94 arranged to receive thetubing 46 as it leaves the cooling device. The coiling device furtherincludes a peripherally grooved forming roller 96 and two peripherallygrooved retainer rollers 98 and 100. As the tubing 46 leaves the driverollers 92 and 94 it passes through the groove of the forming roller 96and then through the grooves of the retainer rollers 98 and 100, therollers functioning to coil the tubing 46 into a helical coil, asindicated generally at 102 in Fig. 6, with a free end 104. A tube 106rotatably supported in the movable block 108 projects horizontally andforms a support for the formed coil of tubing.

The gear 110 is mounted on a rotatable shaft 112 which is driven throughcoupling 114 by the D. C. motor 16, the shaft 112 being journaled in abearing in the frame or plate 116. The gear 110 drives a gear 118 asWell as a gear 120, the drive roller 94 being connected to the gear 120so as to rotate therewith. The gear 120, the roller 94, and the gear 118along with the gear 110 are all rotatable about their own respectivefixed axes.

The roller 92 is mounted for rotation with the gear 122 and on the sameshaft 124, such shaft being carried by a block 126 which is pivoted torotate around the same center as the gear 118, the gear 122 meshing withthe gear 118 so as to be driven thereby. This arrangement permits thetwo drive rollers 92 and 94 which act directly upon the progressingtubing 46 to be separated and brought together at will without changingtheir speed with relation to each other, since they are both driven fromthe same gear 110. It is therefore possible to separate the rollers 92and 94 so as to place the progressing tube 46 between them and to letthe tube 46 enter the grooves in the rollers 96, 93 and 100. In so doingthe apparatus may be adjusted so that the coil 102 thus formed willslightly clear the supporting roller 106.

The supporting roller 106 consists of a suitable size tube held at oneend in the movable block 108 but free to rotate and supported a properdistance down its length by the rollers 128 carried by the supportingarm 130. The forming roller 96 and the retaining rollers 98 and 100 areall adjustably supported on the plate or frame 116 so that such rollerscan be moved inwardly or outwardly, thus governing the diameter of theresultant coil. These rollers 96, 98 and 100 are also arranged to permitthe plane of each of the rollers to be rotated about a horizontal axis.In this way the path o-fthe tube 46 as it moves through the rolls 96, 93and 100 is governed to permit the resultant helical coil of tubing to bewound tight against itself, as illustrated, or separated if desired. Theblock 108 is also adjustable so as to shift the supporting roller 106 tothe posi tion desired with respect to the size of the coil being formed.

The nature of the gear train driving the two rolls 92 and 94 is suchthat there is a tendency for the gear 118 to force the roll 92 down intocontact with the lower tube drive roll 94. Since these rolls 92 and 94are constructed so as to bear upon the tube before they bear upon eachother, the tube passing between the rolls 92 and 94 would beconsiderably distorted unless this tendency was restrained. The work ofdistorting the tubing 46 because of this tendency is suificient withinthe limits of the power required to operate the device to completelystall its operation. The motion of the upper tube drive roll 92 towardthe lower one is therefore restrained by means of an adjustable arm 132which permits a predetermined amount of pressure upon the tube 'as itmoves throughthe rolls. This arrangement permits automatic compensationfor slight variation in the diameter of the tube so that duringoperation there is no slippage. The tube then progresses through thedrive rolls 92 and 94 and against the form roll 96 and through theretainer rollsyand'proceeds to form itself into a helical coil along thesupport arm to whatever practical length is-required. When the desiredlength of coil is reached the tube may be cut at a point just after ithas passed through the seriesof rolls, and the out ch? portion removedtopermit another one to be formed.

In one setup We have rnade'the motor 16 for driving the tube coilingdevice a one-half horsepower direct current motor. This motor derivesits power from the special type of motor generator set knowncommercially as an amplidyne. This amplidyne controls the current to themotor 16 so that the motor drives the drive rolls 92and' 94 with a'constant pull or torque on the tubing 46 as it emerges from the press sothat the coiling device coils the tubing at the same rate as the tubingis extruded by the press. This is very important as the tubing as itemerges from the press and before it is cooled has 'very littleresistance to damage and will buckle or stretch if the coiling devicedoes not operate to coil the tubing at the same rate as it is extrudedfrom the press. With this type of control for the D. C. motor, the driverollers 92 and 94 will propel the tubing at the same rate that itemerges from the extrusion press, and speeds from zero velocity up tothe maximumextrusionspeed in the neighborhood of 300 feet per minutehave been satisfactorily handled without damage to the tubing with thecontrol of the type referred to.

The control embodies provisions for setting the tension exerted by thedrive rolls 92 and 94 on the tubing, and with the size of tubing we havemade and coiled a selected tension between eight and fifteen pounds isusually employed. Once the control-has been set the tension remainsconstant even when the tubing is not being extruded, as for example whena new billet is being placed in the cylinder 30.

In the control system of the type indicated for the motor 16, theprimary 200 of the transformer indicated generally at 202 is energizedby the usual A. C. current supplied, and the transformer 202 inconjunction with the rectifier 183 furnishes the current to the field.20 4 of the D. C. motor 16 connected across L2 and F1. The armature ofthe motor 16 is indicated at 206.

The amplidyne includes a generator having an armature 208 and a field210, the amplidyne generator being driven by any suitable source, suchas an electric motor (not shown). Line P4 of the amplidyne exciter fieldis connected to the positive side of the rectified voltage through thevariable resistor 212. Line P5 of the amplidyne exciter field is thenegative line through the 300 ohm potentiometer torque control 214, thisbeing adjustable to set the torque that the driver rollers 92 and 94will exert on the tubing 46. When the D. C. motor starts to draw thecurrent through its field because of the increased load on the motor thevoltage at point F1 is lowered, causing a difference of potentialbetween the lines F5 and F4, which puts exciter voltage through theamplidyne field. This in turn causes the amplidyne to generate morevoltage for the armature 206 of the D. C. motor and gives the D. C.motor more torque. As the load on the D. C. motor decreases, the voltageat point F1 of the D. C. motor field is raised, causing a smallerditference of potential between lines F5 and P4 of the amplidynegenerator which lowers the exciter voltage, which in turn lowers thevoltage to the D. C. motor and reduces the D. C. motor torque. Thiscontrol is extremely sensitive and responsive, and accurately controlsthe torque output of the D. C. motor 16 so that the drive rollers 92 and94 will maintain a constant torque on the tubing 46 at all velocitieswithin its range of speed.

While we have illustrated and described a preferred embodiment of ourinvention, it is understood that this is capable of modification, and wetherefore do not wish to be limited to the precise details set forth butdesire to avail ourselves of such changes and alterations as fall withinthe purview of the following claims.

We claim:

1. A tube coiling device comprising a pair of cooperative peripherallygrooved drive rolls, a forming and a series of retainer rolls arrangedto coil tubing in the form of a free ended helix, one of said driverolls being rotatable on a fixed axis, means freely mounting the otherof said drive rolls for rotation about an axis shittable toward and awayfrom said fixed axis, said drive rolls being arranged to receive saidtubing in driving relation therebetween and being operable to propelsaid tubing past said other rolls, said mounting means having adjustablemeans to limit the movement of the axis of said other drive roll onlytoward said fixed axis so that said drive rolls will automatically spacethemselves to accommodate variations in the diameter of said tubing,common means for driving said drive rolls at the same rate of speed butin opposite directions, said last-mentioned driving means beingconstructed and arranged with respect to said mounting means for theshiftable drive roll so as to apply torque to said shittable drive rollin a direction to produce torque reaction of the shiftable drive rollwhich biases said shiftable drive roll toward the other of said driverolls, and a horizontally extending arm freely projecting from saiddevice and arranged to support said coil of tubing after it is formed sothat a severed coil of such tubing may be freely removed with outinterfering with the operation of said cooling device.

2. Apparatus for extruding, cooling and bending seamless metal tubingcomprising a continuous ram type extruding press for hot extrudingcontinuous metal tubing of constant diameter, a cooler adjacent saidpress having a free path through which the hot tubing is pulled as it isbeing rapidly cooled, shaped propulsion rolls for pulling said tubingthrough said cooler, means for driving said rolls for pulling saidtubing at extrusion speed and so as to exert a constant and uniform pullon said tubing whereby the diameter or" said tubing remains constant andis fixed by rapid cooling, a tubing bending device comprising ofisetbending rolls, said. propulsion rolls moving said rapidly cooled tubinginto and through said bending device, said bending rolls being disposedso as to apply bending pressure at spaced intervals on only one side ofthe tubing whereby said tubing maintains the constant diameter of saidchilled tubing.

3. Apparatus according to claim 2 wherein said bending rolls are spacedand disposed so as to bend said tubing into a coil in the form of ahelix of substantially uniform diameter and means arranged to receiveand support the coil of tubing as it is being formed while leaving theleading end of said helix free.

4. Apparatus according to claim 2 wherein said cooler includesprovisions for directing jets of cooling liquid against said tubing asit moves through said cooler.

5. Apparatus for extruding seamless metal tubing comprising a continuousram type extruding press for hot extruding continuous tubing of constantdiameter, shaped propulsion rolls engageable with said tubing after thediameter thereof as extruded has been fixed by cooling for pulling saidtubing as it is extruded from the press, means for driving said rollsfor pulling said tubing at extrusion speed and so as to exert a constantand uniform pull on said tubing whereby the diameter of said tubing asextruded remains constant, and a tubing bending device comprising otisetrolls, said propulsion rolls moving said cooled tubing into and throughsaid bending device, said bending rolls being spaced and disposed so asto apply bending pressure at spaced intervals on only one side of thetubing so as to bend said tubing into a coil in the form of a helix ofsubstantially uniform diameter while leaving the leading end of saidtubing free and whereby the diameter of said tubing as extruded remainsconstant and fixed.

References Cited in the file of this patent UNITED STATES PATENTS278,695 Farrell June 5, 1883 278,696 Farrell lune 5, 1883 403,940 KerrMay 28, 1889 972,928 Schneider Oct. 18, 1910 1,028,102 Erickson June 4,1912 1,417,249 Kardong May 23, 1922 1,561,577 Trautman Nov. 17, 19251,741,815 Boynton Dec. 31, 1929 1,769,205 Clark July 1, 1930 1,782,692Lawson Nov. 25, 1930 1,849,044 Summey Mar. 8, 1932 2,048,557 Mickelsonet a1 July 21, 1936 2,167,971 Gadden Aug. 1, 1939 2,176,365 Skinner Oct.17, 1939 2,291,204 Betterton July 28, 1942 2,347,639 Platt Apr. 25, 19442,359,453 Waldron Oct. 3, 1944 2,377,908 Slaughter June 12, 19452,453,165 Thornburgh Nov. 9, 1948 2,720,310 Yack Oct. 11, 1955 FOREIGNPATENTS 284,085 Great Britain Jan. 26, 1928 410,624 Great Britain May24, 1934 593,508 Great Britain Oct. 17, 1947 646,296 Great Britain Nov.22, 1950 660,747 Great Britain Nov. 14, 1951

